Continuous automated plastic molding method

ABSTRACT

Disclosed is a method for continuously molding plastic parts. Basically, the method can be practiced with apparatus which comprises a pair of spaced, rotatable, indexable trunnion transfer units or wheels having a plurality of cradles thereon for receiving and transporting carrier bars. The wheels are indexable to a number of stations at which various activities take place and are positioned on either side of the mold area of a conventional molding machine. A carrier bar having affixed thereto a plurality of cores for the part to be molded, for example, is transported by the rotating wheel from the bottom of the first wheel to a first station where an insert may be added to the core and thence to the top position of the wheel where the carrier bar is transferred to a conveyor which in turn transports the carrier bar to the mold. After completion of the molding cycle, the carrier bar with the molded parts thereon, is transported by the conveyor to the top of the second wheel where it is inserted thereon. The second wheel is then rotated to a first station where additional parts may be affixed to the molded part and thence to a second station where the molded parts are unloaded from the cores on the carrier bar. After unloading, the parts are moved by conveyor or other means for further processing or are deposited in a storage container. Thereafter, the second wheel is indexed to a third station where the empty carrier bar is transferred to an inclined track for return to the first wheel where the process is repeated. The method and apparatus can be employed to transport a carrier bar having either cores or inserts thereon depending upon the part to be molded.

This is a division of application Ser. No. 241,934 filed Apr. 7, 1972.

BACKGROUND OF THE INVENTION

It is desirable in the molding of plastic parts to produce such parts ata high production level. One method of obtaining a high production rateis to employ a molding machine with a plurality of cooperating or matingmold parts. As described in U.S. Pat. No. 3,309,739 for a plasticinjection molding machine, the molds can be mounted on a shuttle tableso that one set of mold parts are closed and the mold cavity thereininjected with plastic to form the desired part while one or more othersets of molds are available for cooling, removal of finished parts andloading into the mold cavity of any special part or insert. The shuttletable is then moved to align the mold with an injection station in themolding machine while the mold which has just been injected with plasticis moved to an ejecting station. Each mold may contain a plurality ofcavities so that with each injection of plastic, a plurality of partsare formed. While such a method and apparatus is generally satisfactory,to further increase the production level, additional machines arerequired which in turn require additional operators.

SUMMARY OF THE INVENTION

In essence, the method of the present invention and the apparatus forconducting the method comprises a pair of rotatable, indexable trunniontransfer units or wheels which may be indexed to a number of stations atwhich various activities take place. A carrier bar having positionedthereon a plurality of cores, for example, is positioned on the firstwheel at the bottom thereof. The wheel is then indexed to a firststation where inserts are fed into the cores after which the wheel isindexed to a second station at the top of the wheel where the carrierbar is transferred from the wneel to a conveyor. The conveyor transportsthe carrier bar to the mold where molding of the plastic part takesplace. After the molding cycle is completed, the carrier bar with themolded parts thereon is transported by the conveyor to the top of thesecond wheel and transferred from the conveyor to the wheel. The secondtrunnion transfer unit or wheel is then indexed to a first station whereadditional parts can be added to the molded part and again indexed to asecond position where the molded parts are removed from the core anddeposited on a conveyor for further processing or into a storagecontainer. The second wheel is finally indexed to a fourth position sothat the empty carrier bar is positioned at the bottom of the wheel inan inverted position. The bar is then transferred to an inclined trackdown which it slides to the first wheel wherein the process is repeated.

The carrier bar can be designed to transport either cores or insertsdepending on the part to be made.

DRAWINGS

The invention will be better understood upon consideration of thefollowing detailed description of a specific embodiment thereof, whenread in conjunction with the appended drawings, in which:

FIG. 1 is a perspective view of the molding apparatus of the presentinvention;

FIG. 2 is a perspective view of a carrier with mold cores projectingtherefrom, the carrier being transported through the apparatus formolding and fabrication of a plastic part;

FIG. 3 is a side elevational view in cross-section illustrating asyringe barrel made with the method and apparatus of the presentinvention;

FIG. 4 is a top plan view of the apparatus illustrating the position ofthe various portions thereof;

FIG. 5 is a side plan view of the apparatus of FIG. 4 illustrating theposition of the various portions thereof and the transport of thecarrier through the apparatus during the molding of a part;

FIG. 6 is a side elevational view of the first trunnion transfer unit orwheel, partly in cross-section, and illustrating the position needlefeeding station in relation to the trunnion transfer unit;

FIG. 7 is a top elevational view of a shot-pin assembly used toaccurately align the trunnion transfer units;

FIG. 8 is a side elevational view of the shot pin assembly of FIG. 7;

FIG. 9 is a side elevational view of the return track and elevatorassembly for returning a carrier from the second trunnion transfer unitto the first trunnion transfer unit;

FIG. 10 is a side elevational view in cross-section of the return trackassembly with a carrier thereon;

FIG. 11 is a top plan view of the needle feeding and loading assembly,illustrating the needle feeding, clamping, and loading assemblies;

FIG. 12 is a side elevational view, partially in cross-section of theneedle feeding, clamping, and loading assembles;

FIG. 13 is a rear elevational view, partially in cross-section of theneedle hopper and shuttle, taken along the line 13--13 of FIG. 11;

FIG. 14 is a side elevational view in cross-section of the needle hopperand shuttle assembly;

FIG. 15 is a partial top elevational view illustrating the needleclamping and releasing assembly;

FIG. 16 is a side elevational view in cross-section taken along the line16--16 of FIG. 15;

FIG. 17 is a side elevational view in cross-section taken along the line17--17 of FIG. 15 and illustrating the needle clamp assembly;

FIG. 18 is a side elevational view in cross-section illustrating theneedle clamp detail;

FIG. 19 is a top elevational view of the carrier ejector assembly aspositioned on the first trunnion transfer unit;

FIG. 20 is a front elevational view of the carrier ejector assemblytaken along the line 20--20 of FIG. 19;

FIG. 21 is a side elevational view of the carrier ejector assembly ofFIG. 19;

FIG. 22 is a partial side elevational view illustrating the chaindriving and stopping mechanism;

FIG. 23 is a partial side elevational view illustrating the chainstopping mechanism detail;

FIG. 24 is a front elevational view of the chain stopping mechanism ofFIG. 23;

FIG. 25 is a top elevational view of the sheath pick-up drum;

FIG. 26 is a top elevational view illustrating the sheath orienting slotin the orientation escapement and illustrating orientation of thesheaths prior to transfer to the sheath pick-up drum;

FIG. 27 is a side elevational view taken along the line 27--27 of FIG.25;

FIG. 28 is a top elevational view of the sheath loading assembly;

FIG. 29 is a rear elevational view of the sheath loading assembly takenalong the line 29--29 of FIG. 28;

FIG. 30 is a side elevational view, partially in cross-section, of thesheath loading assembly taken along the line 30--30 of FIG. 28;

FIG. 31 is a side elevational view of the second trunnion transfer unitillustrating the position of the sheath feeding, unloading and carrierejection stations in relation to the trunnion transfer unit andillustrating a portion of the part transport tubes and conveyor;

FIG. 32 is a top elevational view of the transport tubes positioned onthe conveyor for transporting the molded parts;

FIG. 33 is a top elevational view of the molded part unloading assemblyfor stripping the molded parts from the cores on the carrier;

FIG. 34 is a side elevational view of the unloading and strippingassembly in FIG. 33;

FIG. 35 is a top elevational view of the transport tubes positioned onthe part conveyor and a portion of the part unloading and strippingassembly;

FIG. 36 is a side elevational view, partially in cross-section, of theassembly of FIG. 35;

FIG. 37 is a side elevational view of the part conveyor and parttransfer assembly illustrating transfer of the molded parts from thetransfer tubes on the conveyor to the part transfer assembly;

FIG. 38 is a rear elevational view, partially in cross-section, of theconveyor and part transport tubes taken along the line 38--38 of FIG.37;

FIG. 39 is a front elevational view, partially in cross-section, of thepart transfer assembly of FIG. 37;

FIG. 40 is a side elevational view, partially in cross-section, of thepart transfer assembly of FIG. 35;

FIG. 41 is a side elevational view, partially in cross-section, of apart in which the carrier employed in the method and apparatus of thisinvention has cores projecting therefrom;

FIG. 42 is a top elevational view of a molded part made by the methodand apparatus of this invention and in which the carrier transports theinsert;

GENERAL DESCRIPTION

The method and apparatus 40 of this invention can be employed to produceplastic parts of various types. Depending upon the part to be molded, acarrier bar 50 which is transported through the apparatus 40 ashereinafter described can be designed to transfer either cores orinserts thereon as required by the part to be formed. To produce a part45 such as illustrated in FIG. 3, the carrier 50 can be designed totransport mold cores 51 and inserts 48 for the part. Thus, the parts 45are molded about the core 51 and the insert 48. On the other hand, thecarrier 50 can be designed to transport the insert 31 only when a part30 such as illustrated in FIG. 42 is to be molded. For such a part 30,the carrier 50 transports the insert 31 to the mold where the plasticmaterial 32 is injected about the insert 31. The apparatus of thepresent invention is portable and can be utilized with a conventionalmolded machine 99 such as a Hydraulic Press Manufacturing Companymolding machine having a 14 ounce capacity and a 200 ton clamp.

A general understanding of the method and apparatus 40 can be attainedby reference to FIGS. 1, 2, 4, and 5 which illustrate the over-allapparatus. While the method and apparatus 40 can be utilized tofabricate a variety of plastic parts, for convenience the system will bedescribed with reference to the production of the injector or barrelportion 40 of a syringe 45 as illustrated in FIG. 3. The syringe 45comprises a barrel 46 including a hub 47 which is molded about a cannulaor needle 48. A sheath 49 is inserted onto the hub 47 of the barrel 46to protect the needle 48 prior to use. The carrier 50 is accordinglydesigned for production of the injector 45 and includes a plurality ofcores 51 shaped to conform with the barrel 46 and hub portion 47 of theinjector 45 and projecting from the base 53 of the carrier 50. Acylindrical opening 52 in the cores 51 receives and supports the needle48 prior to molding.

As best seen in FIG. 1, the apparatus comprised a first trunniontransfer unit 70 positioned on one side of the molding machine 99 and asecond trunnion transfer unit 75 positioned on the opposite side of themolding machine 99. A movable chain assembly 130 transports the carrier50 from the first trunnion transfer unit 70 through the molding machine99 where the part is molded to the second trunnion transistor unit 75where additional parts such as the sheath 49 can be added and the partstripped from the cores 51 on the carrier 50. The empty carrier 50 isthen conveyed from the second trunnion transfer unit 75 by means of areturn track assembly 250 to an elevator assembly 260 which transfersthe carrier 50 to the first trunnion transfer unit 70 where the processis repeated.

To produce the injector 45, a suitable carrier 50 having cores 51thereon as previously described is inserted at the 6 o'clock position ofthe first trunnion transfer unit 70. The trunnion 70 is then rotated tothe 3 o'clock position where a needle feeding assembly 100 insertsneedles 48 into the opening 52 of the cores 51. The trunnion 70 is thenrotated to the 12 o'clock position where the carrier 50 is ejected ontothe chain assembly 130. The carrier 50 with the loaded needles 48 in thecores 51 is then conveyed to the molding machine 99 where the mold isclosed about the cores 51 and the plastic injected. The mold is thenopened and the carrier 50 with the molded parts 45 thereon is conveyedto the second trunnion transfer unit 75 where the carrier 50 is loadedonto the transfer unit 75 at the 12 o'clock position thereof. Thetransfer unit 75 is further rotated in a clockwise direction to the 3o'clock position where sheaths 49 are inserted onto the hub 47 of theinjector 45. The sheaths 49 which are previously molded are stored in ahopper 150 and are fed to an orientation excapement 151. Here thesheaths 46 are oriented into a proper position as hereinafter explainedand fed to a sheath feeder assembly 165 which loads the sheaths 49 ontothe barrel 46 of the injector 45. The transfer unit 75 is then rotatedto the 5 o'clock position where the molded parts 45 are stripped fromthe cores 51 of the carrier 50. The parts 45 can then be conveyed toother equipment for further processing or may be collected in suitablecontainers. The transfer unit 75 is subsequently rotated to the 6o'clock position where the carrier 50 in an inverted position is ejectedonto the return track assembly 250 and is conveyed to the elevator 260.The carrier 50 is then inserted into the first trunnion transfer unit 70and the process is repeated.

The trunnion transfer wheels 70, 75 are indexed by means of a 12-stopGeneva-drive. Geneva drives are conventionally utilized for indexingpurposes and are described in Mechanisms and Dynamics of Machinery, 2ndEdtiion by Mabie and Ocvirk at pages 32 and 33. Referring to FIGS. 6, 7,and 8, FIG. 6 illustrates the first trunnion transfer wheel 70. Transferwheel 70 includes 12 spaced cradles 71 positioned evenly around theperiphery of the trunnion transfer unit 70 which receive and support thecarrier 50 as they are transported by the wheel 70 to the variouspositions. In the operation of the apparatus, the trunnion transferunits 70, 75 are advanced with an intermittent rotary motion, thedistance of each interval of advance being such as to move each cradle71, 76 into the position previously occupied by the one immediatelyahead of it. This intermittent advance of the trunnion transfer units70, 75 is effected by a Geneva-drive and clutch and brake combination(not shown). In the embodiment illustrated, the trunnion transfer units70, 75 are indexed by using a 12-stop Geneva-drive being driven by areducer and electric clutch-brake. The Geneva-drive is coupled to anelectric motor by a clutch, the output from the clutch driving agear-reducer through a brake. By a simultaneous releasing of the clutchand engaging of the brake, transmission may be effectively instanteouslystopped. The output from the gear-reducer drives a Geneva-drive inputgear which has a driving pin projecting from its outer edge. TheGeneva-drive results from the meshing of the pin with correspondingslots in a Geneva-drive output gear. While the input gear rotatesuniformly and at a constant speed, power is transmitted to theGeneva-drive output gear intermittently because the pin moves inwardlyand outwardly in the slots for part of its travel and is thenineffectual to rotate the gear. The intermittent drive is transmitted tothe trunnion transfer unit 70, 75. FIGS. 7 and 8 illustrate a shot-pinassembly 55 which accurately lines up the trunnion transfer units 70, 75at the various positions. On a signal produced, for example, after theneedles 48 are fed into the cores 51, as hereinafter explained, alatching relay holds the contacts of the motor control relay closed. Alobe on the shot-pin cam 56 (FIG. 7) energizes another relay which inturn breaks the connection to the motor drive and the wheel 70, 75 isstopped as the brake is released. While the Geneva-drive clutch andbrake combination stops the transfer wheel 70, 75 at the desiredposition, a shot-pin assembly 55 is utilized to accurately align thewheel at the proper position. The shot-pin assembly 55 basicallycomprises a cam 56, a cam follower 57, arm 58 and shot-pin 59. Eachstation on the trunnion transfer unit 70, 75, corresponding to theposition of a cradle 71, 76 includes a bushing (not shown) forengagement with the pin 59. The pin 59 is tapered and as the wheel 70,75 stops at each station, the pin 59, activated by the cam 56, follower57, and arm 58 enters a bushing and accurately lines up the wheel. Theshot-pin assembly 55 is supported by a plate 60 positioned adjacent thetrunnion transfer units 70, 75, the arm 58 thereof pivoted in the centeron a pin 61 at the end of a bracket 62 extending from the support plat60. Likewise, the shot-pin 59 is pivoted to the arm 58 on the sideopposite the cam follower 57 by pivot pins 63 on the end thereof and onthe arm 58, the pins 63 connected by a link 64. The shot-pin 59reciprocates through a bushing 65 which passes through the plate 60; aspring 66 acting to assist the insertion of the shot-pin 59 in thetrunnion transfer units. Each wheel is driven separately by its owndrive and signals.

RETURN TRACK AND ELEVATOR ASSEMBLY

After the molding process is completed and the parts are unloaded fromthe carrier 50 as hereinafter explained, the carrier 50 is ejected fromthe second transfer unit 75 onto the return track 250 in an invertedposition. Referring to FIGS. 5, 9, and 10, the return track 250 lies inan inclined position and connects the bottom or 12 o'clock position ofthe second trunnion transfer units 75 with the elevator assembly 260 andcomprises a pair of spaced channel beams 251 affixed to frame member256. Opposed rollers 252 are affixed to the channel beams 251 along thelength thereof by means of bolts 253 and permit the carriers 50 to slidealong the length of the return track 250, the base 53 being supported bythe rollers 252 and the cores 51 depending through the space between theopposed rollers 252. Accordingly, the carriers 50 are transported fromthe second trunnion transfer unit 75 along the return track 250 to theelevator assembly 260. To provide additional support for the returntrack 250, tie bars 255 are positioned at intervals along the lengththereof, affixed to a pair of opposed depending brackets 254, the otherends of which are fastened to the channel beams 251. The elevatorassembly 260 comprises a support frame 261 which receives the carriers50. The carrier transfer member 262 is normally in an inclined positionin line with the return track 250 and depends by means of pivot 263 froma horizontal plate 265 and is supported on the opposite end by ashoulder 266 affixed to and projecting from the support frame 261. Abracket 264 projects from the transfer member 262 through an opening 267in the plate 265. The bracket 264 is gripped for transfer of the entireassembly as hereinafter explained. As the carrier 50 arrives at thecarrier transfer assembly 262 in the elevator 250, it activates a switch271. The switch 271 in turn activates an air cylinder 268 which includesa reciprocating plunger 269 and a gripping head 270. The head 270 of theair cylinder 268 engages with the bracket 264 of the carrier transferassembly 262 and the cylinder 268 reverses direction to transport thetransfer assembly 262 and carrier 60 in a vertical direction. Thetransfer assembly 262 is first pivoted into a horizontal position andthen transferred to the top of elevator assembly 250, in line with thecradle 71 at the 6 o'clock position of the first trunnion transfer unit70, where a switch 262 is engaged. The switch 262 activates the aircylinders 263 and the head 264 thereof pushes the carrier 50 onto thefirst trunnion transfer unit 70 at the 6 o'clock position thereof.

NEEDLE FEEDING AND LOADING

After the carrier is loaded onto the first trunnion transfer wheel 70 atthe 6 o'clock position thereof, the wheel 70 is rotated in acounterclockwise direction, as previously described, to the 3 o'clockposition to a needle feeding station. With a needle 48 having a point oneither end, care must be exercised so that the points are not damaged.Accordingly, the needles 48 cannot be dropped or pushed into theopenings 52 in the cores 51. A clamp assembly 102 is therefore used tofeed the needles 48 into the cores 51. The needle feeding and loadingassembly 100 basically comprises a hopper and feeding assembly 101 forfeeding the needles 48 to a clamp assembly 102 and an air cylinder 103for transferring the needles 48 from the clamp assembly 102 to the cores51. The entire needle feeding and loading assembly 100 is mounted on astationary plate 104, the clamp assembly 102 being mounted on a baseplate 105 attached to the piston 106 of the air cylinder 103 andslidable on a pair of guide rods 107 so that the clamping assembly 102can be moved from a feeding and clamping position to a loading position.The needle feeding assembly 101 is fully described in U.S. Pat. No.3,631,990, issued Jan. 4, 1972 and comprises a hopper 108 and a shuttle109 for sequentially and singly feeding needles 48 into the clampingassembly 102. A hopper 108 is positioned over each of the clamps 102,the hoppers 108 having a slot 110 at the bottom thereof for passage ofthe needles 48 one at a time. As illustrated in FIGS. 11 through 14,positioned beneath the hopper 108 and in engagement therewith, is areciprocal shuttle 109 which likewise includes a slot 111 into which theneedles 48 drop when the slots 110, 111 in the hopper 108 and theshuttle 109 are in alignment. After a needle 48 is retained within theslot 111 of the shuttle 109, the shuttle 109 is moved transversely. Inengagement with the bottom surface of the shuttle 109 is a fixed block112 having a slot which is in alignment with the needle clamp 102 in theclamping assembly. When the slot 111 in the shuttle 109 which contains aneedle 48 picked up as previously described is in alignment with theslot in the fixed block 112, the needle 48 will drop into position inthe slot for individual loading into the clamp 102. The shuttle 109 ofcourse includes a plurality of slots 111, one for each hopper 108 andclamp 102. A conventional air operated cylinder 113 can be employed toreciprocate the shuttle 109 transversely to transfer needles 48 from theslot 110 in the hopper 108 to the slot in the fixed block 112 (FIG. 14)preparatory to loading them in the clamp 102. Likewise a suitablevibration inducer 114 for the hopper is a ball vibrator in which a steelball is propelled by compressed air around hardened steel braces at highspeed setting high frequency vibrations in all directions.

Referring to FIGS. 17 and 18, the needle clamp 102 comprises a block 115having a V-shaped slot 116 therein which receives a needle 48 inaccurate alignment with the openings 52 in the core 51, and areciprocating jaw 117 for holding the needle 48 in position whileloading into the core 51. The jaws 117 are mounted on a slidable plate118 which in turn by means of an arm 119 is attached to the piston 120of an air cylinder 121, as illustrated in FIGS. 15, 16 and 17. The leverarm, being pivotally mounted on the block or plate 122, will move thejaws 117 out of engagement with the needle 48 as the piston 120 of thecylinder 121 is activated, as best seen in FIG. 15. The jaws 117 areeach guided by the plate 118 and rest in a slot therein so that they canmove individually, and are biased toward the V-shaped slot 116 in theneedle receiving block 115 by a spring 123, as illustrated in FIG. 17.The jaw guiding plate 118, activated by the air cylinder 121, aspreviously described, moves all of the jaws 117 away from the needlereceiving block 115 simultaneously to release the needles 48 after theyare inserted in the openings 52 in the cores 51. Accordingly, the aircylinder 121 is employed only to hold the jaws 117 open for feeding andreleasing of the needles 48; the springs 123 acting to close the jaws117 when the air cylinder 121 is released.

As the needles are dropped from the feeding assembly 101 into the clamps102 as previously described, to prevent needles 48 from accidentallyfalling from the clamps 102 prior to activation of the jaws 117, a guideplate 124 is employed to support one end of the needle 48. When theneedles 48 are all loaded into the clamps 102, the cylinder 103 isactivated to push the entire clamping assembly 102, which is mounted ona base plate 105 which is reciprocal between a needle feeding and needleloading position, toward the carrier 50 whereupon the needles 48 areinserted into the cores 51, as best illustrated in FIGS. 11 and 23. Asthe assembly 102 advances, the guide plate 124 is pushed out of the wayby the plate 105 as it rides on the roller 125 affixed to the guide bar124. (see FIG. 12) The air cylinder 121 controlling the jaws 117 isactivated after the needles 48 are loaded into the cores 51 to releasethe needles 48, as previously described, and the second air cylinder 103thereupon withdraws the entire assembly 102 to the needle feedingposition for feeding of needles 48 into the clamps 102.

CARRIER EJECTOR ASSEMBLY

After the cores 51 on the carrier 50 are loaded with needles 48 at theneedle feeding station, the cradle 71 on the first trunnion transferwheel 70 containing the carrier 50 is indexed to the 12 o'clock positionby rotating the trunnion transfer unit 70 counterclockwise, aspreviously described. Here the carrier 50 is in an upright position,ready to be transferred to the mold (not shown). A carrier ejectorassembly 80 is employed to eject the carrier 50 from the first trunniontransfer wheel 70 at the 12 o'clock position thereof on the conveyorchain 130 and a similar assembly 80 is utilized to eject the emptycarrier 50 from the second trunnion transfer wheel 75 at the 6 o'clockposition thereof onto the return track for returning of the carrier 50to the first trunnion transfer unit 70. The ejector assembly 80 forunloading the carrier 50 from the first trunnion transfer wheel 70 ispositioned at the top of the transfer wheel 70 as best illustrated inFIGS. 19, 20 and 21. The ejector assembly 80 is greater in width thanthat of the transfer wheels 70, 75 so as not to interfere with theirmovement and comprises a pair of opposed end plates 81 fastened to asupport frame 82 by bolts 83 and a pair of guide rods 84 on which slidesthe ejector head 85 and connecting member 86. Projecting laterally fromthe ejector head 85 is an arm 87 from which in turn a bumper 88 ofplastic or rubber projects toward the wheel 70, 75 for contact with thecarrier 50 as the ejector assembly 80 is activated to eject the carrier50 from the wheel 70, 75.

An air cylinder 89 is fastened to the opposite end plate 81, the piston90 therof being connected to the connecting member 86 and the ejectorhead 85. When the air cylinder 89 is activated, the piston 90 thereofdraws the ejector head 85 toward the cylinder 89, the bumper 88contacting the carrier 50 and ejecting it from the cradle 71, 76 in thetrunnion transfer unit 70, 75. In the embodiment illustrated, theejector assembly 80 unloads the carrier 50 from the first trunniontransfer wheel 70 onto a shelf or table where an operator positions iton the chain 130 for transport to the mold 99. If desired, the carrier50 can be ejected directly onto a conveyor

CARRIER TRANSPORT CONVEYOR

After loading of the needles 48 into the cores 51 on the carrier 50 atthe needle feeding station and unloading of the carrier 50 from thefirst trunnion transfer wheel 70, the carriers 50 are transported fromthe first trunnion transfer wheel 70 to the mold 99 and thence to asecond trunnion transfer wheel 75 by an endless chain conveyor 130. Inthe embodiment illustrated, the chain 131 revolves around a pair ofopposed sprockets 132 fastened to the chain support frame 133 and isutilized to convey the carrier 50. The chain 131 must position thecarriers 50 in alignment with the mold 99. As illustrated, two carriers50 are positioned in the mold 99 at the same time so that fourteensyringe barrels 46 are molded during a single molding cycle. Variousmeans can be utilized to drive and stop the chain 131, such as a clutchand brake type arrangement previously described in connection with thedriving means for the trunnion transfer wheels 70, 75. As illustrated,the chain 131 is driven by an air cylinder 134 which drives a rack 135and pinion gear 136 combination; the pinion 136 being affixed to thesprocket 132. In the embodiment illustrated, as best seen in FIG. 4, thechain is driven an equal distance from the first trunnion transfer wheel70 to the mold 99 and from the mold 99 to the second trunnion wheel 75.

The chain driving means is best illustrated in FIGS. 22, 23 and 24. Thechain revolves around a pair of opposed sprockets 132 positioned on thesupport frame 133 adjacent each trunnion transfer wheel 70, 75 so thatthe chain 131 travels from the first trunnion transfer wheel 70 throughthe molding area of the molding machine 99 to the second trunniontransfer wheel 75. A pinion gear 136 is affixed to one of the sprockets132 and is in engagement with a rack 135 driven by an air cylinder 134.The distance the chain 131 travels is selected to position the carriers50 at the mold 99 so that the mold halves can be closed about the cores51 on the carrier 50 prior to the injection of plastic to form the partsbeing molded. As best seen in FIGS. 1 and 4, the carriers 50 are ejectedfrom the 12 o'clock position of the first trunnion transfer wheel 70 bythe carrier ejector assembly 80 as previously described, onto a table orshelf 95. In the embodiment illustrated, when two loaded carriers 50have been ejected onto the shelf 95, an operator pushes them onto thechain 131. To assist in holding the carrier 50 in position on the chain131 while being transported, two plates (not shown) can be affixed tothe chain 131 in an upright position, the distance between the platescorresponding to the length of the two carriers 50. Likewise, thecarriers 50 can be ejected directly onto the chain 131 or otherconveyor. When the carriers 50 are loaded on the chain 131, an aircylinder 134 in engagement with the rack 135 is activated, driving therack 135 a predetermined distance, preselected to position the carriers50 within the mold 99. In turn, the rack 135 drives the pinion gear 136to revolve the sprockets 132, drive the chain 131 and position thecarrier bars 50 in the mold 99. To stop the chain 131 and hold thecarriers 50 in the mold 99, a second air cylinder 137 is employed toactivate a hinged lever 138 with a slot 139 therein engageable with apin 140 projecting outwardly from the sprocket 132. When the cylinder134 and rack 135 and pinion gear 136 combination have moved the chain131 the selected distance to position the carriers 50 in the mold 99,the second air cylinder 137 is activated to pivot the hinged lever abouta pivot pins 141 thereby engaging the slot 139 in the lever 138 with thepin 139 on the sprocket 132 to stop and hold the chain 131. After themolding cycle is completed, the mold 99 is opened and the carriers 50with the molded parts 45 thereon are transported by the chain 131 in amanner described above with reference to loading of the carriers 50 inthe mold 99, to a position adjacent the 12 o'clock position of thesecond trunnion transfer wheel 75.

SHEATH FEEDING AND LOADING

AFter the carrier 50 with the molded syringe barrels 46 on the cores 51thereof is loaded onto the 12 o'clock position of the second trunniontransfer wheel 75, as previously described, the trunnion transfer wheel75 is indexed to a sheath feeding station at the 3 o'clock position ofthe trunnion transfer wheel 75 where the cores 51 with molded syringes45 thereon are in a horizontal position with the needles 48 extendingoutwardly. Here the sheaths 49 are inserted onto the hub 47 of thesyringe barrel 46. Referring to FIGS. 1, 25, 26, 27, 28, 29 and 30,orientation, feeding and insertion of the sheaths 49 onto the hub of thebarrel is illustrated.

A supply of sheaths 49 is placed in the hopper 150 from where they arefed in random fashion through a feed tube 152 to an orientationescapement 151. In the orientation escapement 151 is an orientation slot153 in a horizontal plate (not shown), as illustrated in FIG. 26,through which the sheaths 49 drop with the same side down, asillustrated hereinafter. As illustrated in FIGS. 3 and 41, the sheath 49comprises a tubular element having a slight taper with the open endthereof being of greater diameter than the closed end, the open endfitting on the hub 47 of the syringe barrel 46. The orientation slot 153has a configuration which would be formed by two rectangles of differentwidths with the same center line, the width of the wider rectanglecorresponding essentially to the diameter of the sheath 49 at the openend or greater diameter, the width of the other rectangle correspondingessentially to the diameter of the sheath 49 at the closed end orsmallest diameter, the length of the smaller rectangle essentiallycorresponding to the length of the sheath 49, the length of the widerrectangle being less than the length of the sheath 49. Accordingly, theorientation slot 153 comprises a rectangle, the length thereof beingless than the length of the sheath 49 and the width substantiallycorresponding to the greatest diameter of the sheath 49 with smallerrectangles 156 projecting from the ends of the larger rectangle 154, thewidth of the smaller rectangles 156 essentially corresponding to thediameter of the closed end or smallest diameter of the sheath 49, theoverall length of the orientation slot 153 essentially corresponding tothe length of the sheath 49.

As can be seen in FIGS. 1 and 26, the sheaths 49 slide down a feed tube152 from the hopper 150 and arrive at the slot 153 in the orientationescapement in random fashion. As illustrated in FIG. 26 by dotted lines,since the length of the larger diameter rectangle 154 is less than thelength of the sheath 49, and since the width of the smaller projectingrectangles 156 is less than the width of the open end of the sheath 49,the wider diameter of the sheath 49 is prevented from passing throughthe slot 153. The smaller diameter of the sheath 49 however can passthrough the smaller slot 156 and consequently will drop through the slot156 whereupon the open end of the sheaths 49 can then pass through thelarger diameter slot 154. According, the sheaths 49 will drop throughthe slot 153 with the smallest diameter down, regardless of which waythey were facing when they arrive at the slot 153.

After orientation, the oriented sheaths 49 drop through a tube 157 andpass to a pick-up drum 158 which comprises a revolving table 159 with aplurality of holes 160 on the periphery thereof to receive the sheaths49. The drum 158 revolves on a plate 161 which has seven drop-out holes162 therein which are in alignment with the holes 160 on the pick-updrum 158. As the drum 158 revolves, it picks up a series of orientedsheaths 49 through the tube 157 and transports them to the other side ofthe plate 161 to the drop-out holes 162 on the plate 161. The number ofdrop-out holes 162 in the plate 161 is selected to correspond to thenumber of cores 51 on the carrier 50 so that an equivalent number ofsheaths 49 can be fed as hereinafter explained. Access of the sheaths 50to the drop-out holes 162 is controlled by a cover plate 163 held closedby a lever 164 biased by a spring 166 and opened by a solenoid (notshown). As the solenoid is activated, the cover 163 is drawn back andthe oriented sheaths 49 drop from the pick-up drum 158 to the sheathfeeding station through the drop-out holes 162. Since the sheaths 49,when in the holes 160 in the pick-up drum 158 are in a curved alignment,they must be transferred to linear alignment in the sheath feeder 165for insertion on the syringe barrels 46. This is accomplished bydropping the sheaths 49 from the pick-up drum 158, drop-out holes 162through a series of coiled springs 167 of greater diameter than thesheaths 49, each spring 167 connecting the drop-out hole 162 in thepick-up drum 128 with the sheath cartridge 168 on the sheath feeder 165.The sheath feeder 165 is illustrated in FIGS. 28, 29 and 30 andcomprises a revolving positioning bar 169 having a plurality of sheathcartridge 168 extending therefrom. The positioning bar 169 is rotatablefrom a pick-up position where sheaths 49 are dropped through the coiledsprings 167 into the sheath cartridges 168 to a loading position fromwhich sheaths 49 are loaded onto the hub 47 of the syringe barrel 46. Ascan be seen in FIGS. 28, 29 and 30, an air cylinder 170 connected to alever 171 rotates the positioning bar 169 from the 12 o'clock or pick-upposition counterclockwise to the 9 o'clock or loading position. Theentire positioning bar assembly 169 including the sheath receivingcartridges 168 is supported by a pair of guide rods 172 slidable inopposed journals 172 and is likewise movable from a pick-up position toa loading position, movement of the positioning bar 169 beingaccomplished by a second air cylinder 174. Referring to FIG. 30, thepick-up position of the assembly 165 is illustrated. After the sheathreceiving cartridges 168 are loaded with sheaths 49 as previouslydescribed, the air cylinder 170 is activated to rotate the positioningbar 169 to the loading position where the sheath receiving cartridges168 are in a horizontal position, the open end of the sheath 49 opposedto the needle 48 and hub 47 of the syringe barrel 46 retained on thecore 51. At this point the carrier 50 with the molded syringe barrels 46on the cores 51 thereof is positioned in the cradle 76 of the secondtrunnion transfer wheel 75 at the 3 o'clock position thereof where thecores 51 extend in a horizontal position, opposed to the sheathpositioning bar 169 as previously explained. The second air cylinder 174is activated after the positioning bar 169 is rotated to the loadingposition, to slide the entire assembly 169 forward on the guide rods 172and load the sheaths 49 inserting them on the hub 47 of the syringebarrel 46 as the assembly 169 moves forward.

UNLOADING STATION

After the sheaths 49 are loaded onto the syringe barrels 46, aspreviously described, the molded parts 45 are completed as far as thesecond trunnion transfer wheel 75 is concerned. FIG. 31 best illustratesthe sequence of activities which take place on the second trunniontransfer wheel 75. A carrier 50 enters the cradle 76 on the secondtrunnion transfer wheel 75 at the 12 o'clock position thereof and thewheel 75 is rotated to index the carrier 50 having the molded parts 45thereon at the 3 o'clock or sheath feeding station where the sheaths 49are inserted onto the syringe barrel 46 over the needle 48 as previouslydescribed. The trunnion transfer wheel 75 is then indexed to the 5o'clock position or unloading station for stripping of the molded parts45 from the cores 51. After the parts 45 are stripped from the cores 51they are dropped onto conveying or transfer tubes 201 as hereinafterdescribed, which convey the molded parts 45 to a drop-out assembly 220from this parts 45 can be conveyed for further processing or storage.

The unloading or stripping assembly 180 is illustrated in FIGS. 31, 33and 34 and essentially comprises a pair of opposed, pivoted jaws 181,184 activated by an air cylinder 182 for gripping, stripping, andreleasing of the molded parts 45 from the cores 51. As best seen in FIG.34, the stripping assembly 180 comprises a pair of opposed jaws 181, 184pivoted about pins 183, one of the jaws 184 being connected by a pivotedbat 185 to the piston 186 of the air cylinder 182. The other of the jaws181 has a base plate 187 at the bottom thereof, the end of the baseplate 187 having a curved surface 188, the curved surface 188 of thebase plate 187 mating with a curved depression 189 in the pivoted bar185. The mating of the curved portion 188 of the base plate 187 andpivoted bar 185 results in gripping and releasing of the jaws 181 as thebar 185 moves back and forth. As the air cylinder 182 is activated toclose the jaws 181, 184, the first jaw 184 pivots about the pivot pin183 as the piston 186 of the air cylinder 182 is retracted, drawing backthe pivoted bar 185 thereby bringing the jaw 184 about the pin 183 intoengagement with the molded part 45 on the core 51 depending from thecarrier 50. As the pivoted bar 185 is drawn back, the curved surface 188on the base plate 187 of the jaw 181 rides on the bottom surface of thepivoted bar 185 and when it reaches the flat surface of the bar 185, thejaw 181 pivots about the pin 183 to engage the molded part 45 so thatthe molded part 45 is held firmly in the opposed jaws 181, 185 forremoval of the part 45 from the core 51. The spring 190 acts to hold thejaw 181 open when the air cylinder 182 is in the retracted position.

Referring to FIGS. 31 and 36, the means for moving the strippingassembly 180 downwardly to pull the part 45 from the core 51 isillustrated. As seen in FIGS. 31 and 36, the piston 191 of an aircylinder 192 is moveably attached to a bell crank 193 pivoted on a pin194, the other end of the bell crank 193 being attached to the supportplate 195 of the stripping assembly 180 through a connecting link 196and rod 197. The stripping assembly 180 in turn rides on guide barsmounted in bushings (not shown) so that the entire assembly 180 can bemoved toward and away from the carrier held in the cradle 76 on thetrunnion transfer wheel 75 for gripping and removal of the part 45 fromthe core 51. After the jaws 181, 184 grip the part 45, the air cylinder192 is activated to draw the stripping assembly 180 away from the core51, as previously described, thereby pulling the parts 45 from the cores51. The parts 45 are held within the jaws 181, 184 until the end of thestroke of the cylinder 192 so that the part 45 is positioned over atransfer tube 201, whereupon the air cylinder 182 which controls thejaws 181, 184 is activated to release the jaws 181, 184 and drop thepart 45 into the tube 201 which is mounted on an endless belt 202.

PART CONVEYOR AND TRANSFER ASSEMBLY

After the parts 45 are removed from the cores 51 at the unloadingstation, they are dropped into transfer tubes 201 mounted on an endlessbelt 202 which revolves around a pair of opposed rollers 203; the partscontained within the tubes 201 with the sheath side down. Referring toFIGS. 1, 31, 35, 36, 37 and 38, the part conveyor 200 construction andoperation is apparent. As illustrated in FIG. 1, a plurality of tubes201, seven in the illustrated embodiment since the carriers 50 containseven cores 51 and therefore seven parts 45 are molded at one time, aremounted on a conveyor 202 in an inline position to receive seven parts45 from the stripping assembly 180 as previously described. The moldedparts 45 are then conveyed from the end of the conveyor 202 adjacent thesecond trunnion transfer wheel 75 where they are removed from thecarriers 50, to the opposite end of the conveyor 202 where they aretransferred to a drop-out assembly 220, as best seen in FIGS. 37, 38, 39and 40. As a bank of transfer tubes 201 containing parts 45 reaches theend of the conveyor 202, it goes around the end over the roller 203where a curved plate 204 prevents the molded parts 45 from dropping outof the tubes 201. At the end of the curved plate 204 is a series ofparts receiving feed tubes 205 which receive the syringe barrels 46 withthe open end down for transfer to the drop-out assembly 220.

The drop-out assembly 220, as illustrated in FIGS. 37, 39 and 40comprises a series of receiving tubes 221 for molded parts 45 arrangedin a bank in line at equal distance around the periphery of a rotatingshaft 222. The drop-out assembly 220 is timed to the belt 202 by aconnecting chain 223 and sprockets 224 so that the parts 45 arrive atthe feed tubes 205, the receiving tubes 221 on the drop-out assembly 220are positioned at the outlet of the feed tubes 205. The drop-outassembly 220 is rotated 90° increments by an air cylinder 225 and theloaded parts 45 are prevented from falling out of the bottom of the bankof receiving tubes 221 by a curved cover 226 which seals the ends of thereceiving tubes 221. To cover 226 is controlled by an air cylinder (notshown) so that parts 45 can be dropped on a conveyor (not shown) fortransfer to further processing equipment, or, by leaving the cover 226in place, as the receiving tubes 221 pass the end of the cover 226, theparts 45 will slide out and down a by-pass chute 227 to a storagecontainer (not shown) as illustrated in FIG. 37. By releasing the cover226, the lower-most bank of receiving tubes 221 will be exposed so thatthe parts 45 will drop therefrom.

Synchronization of the various activities which take place on themolding apparatus 40 can be controlled by conventional means asdescribed in connection with the needle feeding and carrier ejectorassemblies. Likewise, all the portions of the apparatus 40 are driven byconventional means except as otherwise described.

What is claimed is:
 1. A method of molding an article employing amolding machine having mold sections for receiving a mold core orinsert, said method comprising:providing a carrier having a mold core orinsert supporting means thereon for presenting the mold core or insertto the mold in said molding machine; providing a pair of opposed,rotatable, indexable, trunnion transfer wheels positioned on each sideof said molding machine and a conveyor arranged for transfer of saidcarrier from one of the trunnion transfer wheels to the other, saidtransfer wheels having a plurality of carrier receiving positionsthereon and receiving and transferring said carrier to various positionsaround the periphery thereof; inserting the carrier in one of saidtrunnion transfer wheels; indexing said transfer wheel to the conveyor;transferring the carrier from said transfer wheel to said conveyor;conveying the carrier from the transfer wheel to the mold in the moldingmachine; molding an article about said mold core or insert on saidcarrier; removing said carrier from the molding machine with the articleremaining on the carrier; conveying the carrier from the molding machineto the other of said trunnion transfer wheels; inserting said carrier onsaid other transfer wheel; indexing said other transfer wheel away fromthe conveyor; and removing the molded article from the carrier.
 2. Themethod of claim 1 including the step of returning said carrier to thefirst trunnion transfer wheel after the molded article has been removedtherefrom.